This invention relates to a virtual machine system comprising a plurality of virtual machines constructed under the control of a host program (also referred to as the virtual machine monitor) on a physical computer system with a guest program operating on each virtual machine, or in particular to a virtual machine system wherein a page table for translating the guest virtual address to the host real address is managed by the host program.
In a virtual machine system for partitioning the real main storage logically and assigning the partitions to one or a plurality of virtual machines, a technique is available as disclosed in JP-A-2001-051900, using a translation table indicating the correspondence between the guest virtual address and the host real address. In the case where the guest program can operate in a plurality of address translation modes and a page table exists for translating the same guest virtual address into different host real addresses in each address translation mode, the technical unit disclosed in JP-A-2001-051900 generates a performance overhead.
In the virtual machine system, there is available a technique, as disclosed in JP-A-07-093221, in which the contents registered in the address translation buffer are saved before switching the guest program and the address translation information is read from the dedicated saving area of the guest program thereby to replace the contents registered in the address translation buffer.